Visualization of World Population from 1970 to 2022

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Understanding the Data:

#Loading packages
import pandas as pd
import numpy as np
import plotly.express as px
from plotly.subplots import make_subplots
import plotly.graph_objects as go
from IPython.display import HTML

#Loading dataset
df = pd.read_csv("C:/Users/Nathan/Documents/Portfolio/Portfolio Data/World Population EDA/world_population.csv")

#Transforming Data
years = ['1970 Population','1980 Population','1990 Population','2000 Population','2010 Population','2020 Population']

#Need to consolidate all "YEAR Population" columns into two variables containing years and corresponding populations

#Copy data
df_by_year = df
#"Melt" selected decade populations into two columns: Year and Population while retaining Country and Continent data
df_by_year = pd.melt(df_by_year,id_vars=['Country','Continent'],value_vars=years)
#Rename newly made columns
df_by_year = df_by_year.rename(columns={'variable':'Year','value':'Population'})
#Drop extra wording from Year data
df_by_year['Year'] = df_by_year['Year'].str.replace(' Population','')
#Sort data by population year then population
df_by_year = df_by_year.sort_values(by=['Year','Population'])

#Determining the number of rows and columns in the data
df.shape

(234, 17)

df.head(5)

	Rank	CCA3	Country	Capital	Continent	2022 Population	2020 Population	2015 Population	2010 Population	2000 Population	1990 Population	1980 Population	1970 Population	Area (km²)	Density (per km²)	Growth Rate	World Population Percentage
0	36	AFG	Afghanistan	Kabul	Asia	41128771	38972230	33753499	28189672	19542982	10694796	12486631	10752971	652230	63.0587	1.0257	0.52
1	138	ALB	Albania	Tirana	Europe	2842321	2866849	2882481	2913399	3182021	3295066	2941651	2324731	28748	98.8702	0.9957	0.04
2	34	DZA	Algeria	Algiers	Africa	44903225	43451666	39543154	35856344	30774621	25518074	18739378	13795915	2381741	18.8531	1.0164	0.56
3	213	ASM	American Samoa	Pago Pago	Oceania	44273	46189	51368	54849	58230	47818	32886	27075	199	222.4774	0.9831	0.00
4	203	AND	Andorra	Andorra la Vella	Europe	79824	77700	71746	71519	66097	53569	35611	19860	468	170.5641	1.0100	0.00

The dataset contains population information on 234 different countries and territories within 17 variables:

• Rank : Ranking from 1 to 234 for each country/territory based on current population size
• CCA3 : The three digit country/territory code associated with each country/territory
• Country : The name of the country/territory
• Capital : The name of the capital for the given country/territory
• Continent : The name of the continent for the given country/territory (Asia, Africa, Europe, North America, South America, and Oceania)
• 2022 Population : The 2022 population of the given country/territory
• 2020 Population : The 2020 population of the given country/territory
• 2015 Population : The 2015 population of the given country/territory
• 2010 Population : The 2010 population of the given country/territory
• 2000 Population : The 2000 population of the given country/territory
• 1990 Population : The 1990 population of the given country/territory
• 1980 Population : The 1980 population of the given country/territory
• 1970 Population : The 1970 population of the given country/territory
• Area (km²) : The land mass of the given country/territory in km²
• Denisty (per km²) : The population density of the given country/territory in people per km²
• Growth Rate : The current population growth rate of the given country/territory
• World Population Percentage : The percentage of the total world population residing in the given country/territory

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Start by ensuring that every column is complete and contains no missing values. This can be done by counting the number of instances that occur in each variable column and comparing it with the known length of the dataset.

A quick and easy way to do this is by generating a bar chart.

#Check each column in the data for missing values
missing = df.notnull().sum(axis=0)

#Generate Bar plot for each variable in the dataset counting the number of non-missing instances
fig = px.bar(x=missing.index,
             y=missing.values,
             text=missing.values, #include the number of non-missing values inside each bar on the plot for clarity
             title='World Population Dataset: Total Number of Data Points (out of 234 rows)'
            )
fig.update_traces(hovertemplate='<br> Variable: %{x} </br> Number of Instances: %{y}')
fig.update_layout(xaxis_title='Dataset Variables',yaxis_title='Number of Instances')
fig.show(renderer='notebook')

Since every column contains 234 instances, we can assume there are no missing values in the data.

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To better understand the structure of the data, we may wish to know how many countries and territories are being accounted for in each continent. This can also be done using a bar chart by grouping and counting the number of Country instances within each Continent level.

#Count the number of countries/territories in each continent
country_counts = df.groupby('Continent')['Country'].count()

#Generate 
fig = px.bar(x=country_counts.values,
             y=country_counts.index,
             color=country_counts.index, #add color to easily differentiate between each continent
             text=country_counts.values, #include the number of countries/territories in each continent on bar plot
             color_discrete_sequence=px.colors.sequential.Peach[::-1],
             title='World Population Data: Number of Countries & Territories per Continent')
fig.update_traces(hovertemplate='<br> Continent: %{y} </br> Number of Countries Included: %{x}') #edit hovertext for clarity
fig.update_layout(xaxis_title='Number of Countries & Territories',yaxis_title='Continent')
fig.show()

• There is clearly an unequal number of countries and territories accounted for on each continent, however this is to be expected since the shapes and sizes of both continents and countries are not uniform
• Africa has the greatest number of instances with 57 countries and territories included in the data
• South America* has the lowest number of instances with 14 countries and territories included in the data

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Visualizing the Data:

We can begin by looking at the total world population across the previous five decades to get to start to understand the change over time. Since the data already contains information on the Continent and Country or territory, we can use a filled area plot to see the total world population along with each continent's and country's contribution.

#Generate filled area plot for total population along with continent and country breakdown
px.area(df_by_year,x='Year',y='Population',color='Continent',line_group='Country',
        color_discrete_sequence=px.colors.sequential.Agsunset)

Notice:

• The world population was about 4 billion in the 1970's but is now nearly 8 billion, roughly doubling in the past five decades

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The data contains two variables which have a clear link to one another as well as a population: Area (km²) and Density (per km²)

fig = px.choropleth(data_frame=df,
                   locations='Country',
                   locationmode='country names',
                   color='Area (km²)',
                   color_continuous_scale=px.colors.sequential.Bluyl,
                   title='Total Land Mass by Country',
                   template='ggplot2',
                   projection='natural earth'
                   )
fig.update_geos(lataxis_showgrid=True,
                lonaxis_showgrid=True,
                showocean=True, oceancolor="LightBlue",
                showlakes=True, lakecolor="LightBlue")
fig.show()

Notice:

• Representing the information in a Winkel Tripel projection makes the most sense since it helps preserve true land mass with minimal distortion
• Russia clearly has the greatest amount of available land mass with about 17 million square kilometers of land mass
• The United States, Canada, Brazil, Austalia, and China are the next largest countries with anywhere from 7.5 to 10 million square kilometers of land mass

fig = px.choropleth(data_frame=df,
                   locations='Country',
                   locationmode='country names',
                   color='Density (per km²)',
                   color_continuous_scale=px.colors.sequential.OrRd,
                   title='Total Population Density by Country',
                   template='ggplot2',
                   range_color=(0,150),
                   projection='natural earth'
                   )
fig.update_geos(lataxis_showgrid=True,
                lonaxis_showgrid=True,
                showocean=True, oceancolor="LightBlue",
                showlakes=True, lakecolor="LightBlue")
example = fig
fig.show()

Notice:

• Although China is among the largest countries in the world in terms of land mass, it also has one of the highest population densities
• India and The Netherlands have the highest population densities of any other country or territory with over 400 residents per square kilometer
• Europe and Asia appear to have the highest overall population densities while South America appears to have the lowest

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Since the data contains information on the world population split by each country and territory's contribution, it may be easier to get a general understanding by visualizing each countries and territories impact by viewing the information on a choropleth map. This makes it possible to view the aggregated population data in a geographic way.

Lets start by looking at a map of the current 2022 Population:

#Generate a choropleth map to visual the current world population
fig = px.choropleth(data_frame=df,
                   locations='Country',
                   locationmode='country names',
                   color='2022 Population',
                   color_continuous_scale=px.colors.sequential.RdBu[::-1],
                   range_color=(0,1000000000),
                   title='World Map Indicating 2022 Populations',
                   template='ggplot2',
                   projection='natural earth')
#Set up coloration and grids for clarity on borders and position
fig.update_geos(lataxis_showgrid=True,
                lonaxis_showgrid=True,
                showocean=True, oceancolor="LightBlue",
                showlakes=True, lakecolor="LightBlue")

Notice:

• India and China are currently the most populated countries with a 700 million population gap between the next most populated country
• The most populated countries of each continent are China, The United States, Brazil, Nigeria, Russia and Australia

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Next, viewing the same map as an animation over the past 50 years can help see if there are any obvious trends in population growth in specific regions across the globe while simultaneously being able to compare them with the rest of the world.

#Generate a choropleth animation showing the change in country/territory populations for each decade from 1970-2020
fig = px.choropleth(data_frame=df_by_year,
                   locations='Country', #Column used to identify countries
                   locationmode='country names', 
                   color='Population', #Column used to identify color intensity
                   animation_frame='Year', #Column used to idenify each animation frame
                   color_continuous_scale=px.colors.sequential.RdBu[::-1],
                   range_color=(0,1000000000), #set limit on colorscale, India and China are so large the rest seem unchanged
                   title='World Map Indicating Populations: 1970 - 2020',
                   template='ggplot2',
                   projection='natural earth') #change map projection type to Winkel Tripel

#Include longitude, latitude, and water markings for clarify and visual appeal
fig.update_geos(lataxis_showgrid=True,
                lonaxis_showgrid=True,
                showocean=True, oceancolor="LightBlue",
                showlakes=True, lakecolor="LightBlue")

Notice:

• Asia clearly has had the most populated areas in the world of the past five decades
• Although some of the nation's populations seem to be growing, many of the European countries have remained nearly unchanged in a 50 year span

Since roughly half of the current world population reside in China, India, and Pakistan alone, we isolate Asia to take a closer look at its changes over the past 50 years.

#Generate the same choropleth map as before, this time changing the scope of the map from the entire world to only Asia
fig = px.choropleth(data_frame=df_by_year,
                   locations='Country',
                   locationmode='country names',
                   color='Population',
                   animation_frame='Year',
                   color_continuous_scale=px.colors.sequential.RdBu[::-1],
                   range_color=(0,1000000000),
                   title='Asia Population Density Map: 1970 - 2020',
                   template='ggplot2',
                   scope = 'asia')
fig.update_geos(lataxis_showgrid=True,
                lonaxis_showgrid=True,
                showocean=True, oceancolor="LightBlue",
                showlakes=True, lakecolor="LightBlue")
fig.show()

Notice:

• In the past five decades, India's total population nearly triples in magnitude showing a very high growth rate in comparison to the rest of the world
• China shows a similar increase nearly doubling it's total population as well in the same amount of time
• Indonesia and Pakistan hold large populations especially when taking their total land mass into account. For reference, Indonesia and Pakistan have population sizes of comparable size to the United States. However, their land masses are between 4 and 10 times smaller than the United States making their population densities one of the highest in the world.

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Taking a closer look at each continents contribution to world population levels, we can start by looking at the 2022 Population and see the average population sizes of their corresponding territories and countries.

#Find the average population by continent and sort values in a descending order
continent_populations = df.groupby('Continent')['2022 Population'].mean().round().sort_values(ascending=False)

#Generate a bar plot to visual each continent's average population
fig=px.bar(x=continent_populations.index,
           y=continent_populations.values,
           color=continent_populations.index, #color each continents bar according to its population
           text=continent_populations.values, #include average population amount on each bar for clarity
           color_discrete_sequence=px.colors.sequential.Darkmint[::-1],
           title='Average 2022 Population by Continent'
          )

fig.update_layout(xaxis_title='Continents',
                  yaxis_title='Average Population Count')

fig.update_traces(hovertemplate='<br> Continent: %{x} </br> Average Population: %{y}') #update hover information for inspection

fig.show()

Notice:

• Asia has the greatest average population density compared to all of the other continents
• Asia's average population is nearly the same as all the remaining continents average populations combined
• Although their overall land masses are greatly different, North America and Europe have a nearly identical average population

Aside from the current world population numbers, inspecting average population sizes from the past few decades could help identify any apparent traits. From the data, we can pull the 2020 Population,2010 Population,2000 Population,1990 Population,1980 Population,and 1970 Population numbers and generate similar plots for reference.

years = ['2020 Population','2010 Population', '2000 Population', '1990 Population','1980 Population', '1970 Population']

#Calculate the average country/territory population for each continent
cont_pop_years = df.groupby('Continent').mean().round()
#Drop unneeded variables
cont_pop_years = cont_pop_years.drop(['Area (km²)', 'Density (per km²)', 'Growth Rate','World Population Percentage'],axis=1)
#Reintroduce continent are variable
cont_pop_years.reset_index(inplace=True)

#Combine all the population year variables into two variables: one containing the year and one containing the corresponding pop.
cont_pop_years = pd.melt(cont_pop_years,id_vars=['Continent'],value_vars=years)
cont_pop_years = cont_pop_years.rename(columns={'variable':'Year','value':'Population'})
#Remove ' Population' from Year variable and just leave year
cont_pop_years['Year'] = cont_pop_years['Year'].str.replace(' Population','')

#Reorganize the order of the data to match earlier plot to see progression more easily
cat = ['Asia','South America','Africa','North America','Europe','Oceania']
cont_pop_years['Continent'] = pd.Categorical(cont_pop_years['Continent'],categories=cat)
cont_pop_years = cont_pop_years.sort_values(by=['Continent','Year'])

#Generate animated bar plot of average country population by continent the change over decades
fig=px.bar(cont_pop_years,
               x='Continent',
               y='Population',
               color='Continent',  
               color_discrete_sequence=px.colors.sequential.Darkmint[::-1],
               title='Average Population by Continent: 1970 - 2020',
           animation_frame='Year',
           range_y=[0,95000000]
              )
#Rename axes and hover infromation for clarity
fig.update_layout(xaxis_title='Continents', yaxis_title='Population Count')
fig.update_traces(hovertemplate='<br> Continent: %{x} </br> Average Population: %{y}')
fig.show()

Notice:

• Asia has had the largest average population doubling its average size since the 1970's while Oceania has remained the smallest
• South America and Europe had nearly identical average population sizes 50 years ago, but now South America's average population size has doubled while Europe's has only remained steady
• Africa had the second smallest average population size in the 1970's but became the third largest in the past 30 years

---

Aside from the average values, we can compare the total population sizes of each continent to one another as well as see their percentage level contributions to the total world population using a pie chart. For a baseline, we can first inspect the levels from the 2022 Population sizes.

#Generate a pie chart to visualize the proportion each continent contributes to the current total world population
fig = px.pie(df,
             values='2022 Population',
             names='Continent',
             color_discrete_sequence=px.colors.sequential.Magenta[::-1],
             title='Total 2022 Population by Continent',
             hole=0.25
            )

fig.update_traces(textinfo='label+percent+value') #update each slices information for better readability

fig.show()

Notice:

• Asia contributes nearly 60% of the total world population at roughly 4.7 billion people
• Although it has the second highest average population, South America only contributes about 6% of the world population which is the second lowest
• Although it has the second lowest average population, Europe contributes about 10% of the world population which is the third largest

Also using the 2020 Population,2010 Population,2000 Population,1990 Population,1980 Population,and 1970 Population data, we can generate similar visuals for their total population sizes and see how certain continents and their overall contributions have shifted over time.

populations = [['1970 Population','1980 Population'],['1990 Population','2000 Population'],
               ['2010 Population','2020 Population']]
i=1

fig = make_subplots(rows=3,cols=2,specs=[[{'type':'domain'},{'type':'domain'}],[{'type':'domain'},{'type':'domain'}],
                                         [{'type':'domain'},{'type':'domain'}]],
                    subplot_titles = ['Total 1970 Population','Total 1980 Population','Total 1990 Population',
                                      'Total 2000 Population','Total 2010 Population','Total 2020 Population'],
                    horizontal_spacing=0.3,
                    column_widths=[0.5,0.5],vertical_spacing=0)

for pop in populations:
    
    fig.add_trace(
    go.Pie(values = df.groupby('Continent')[pop[0]].sum().sort_values(ascending=False),
           labels = df.groupby('Continent')[pop[0]].sum().sort_values(ascending=False).index,
           name='',
           marker=dict(colors=px.colors.sequential.Magenta[::-1]),
           texttemplate='<br>%{label}</br>%{percent}</br>%{value}',
           textposition='outside',
           pull = [0,0.1,0.1,0,0,0]
    ),
    row=i,
    col=1
    )
    fig.add_trace(
    go.Pie(values = df.groupby('Continent')[pop[1]].sum().sort_values(ascending=False),
           labels = df.groupby('Continent')[pop[1]].sum().sort_values(ascending=False).index,
           name='',
           marker=dict(colors=px.colors.sequential.Magenta[::-1]),
           texttemplate='<br>%{label}</br>%{percent}</br>%{value}',
           textposition='outside',
           pull = [0,0.1,0.1,0,0,0]
    ),
    row=i,
    col=2
    )
    i+=1

fig.update_layout(height=1500,showlegend=False,title='Total World Population: 1970 - 2020')
fig.show()

Notice:

• Asia has had the largest population over the past 50 years, increasing its total contribution by only 1% while doubling in size
• Europe had the second largest population until Africa overtook it around the turn of the century
• Europe dropped from having roughly 18% of the world population in the 1970's to having less than 10% in the 2020's
• North America, South America and Oceania have remained the three least populated continents since the 1970's and have remained nearly constant in their percentage contributions to the total world population

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After looking at each continent as a whole, we can identify which countries and territories have contributed the most and least to the current world population.

#Calculate the top 5 most populated countries/territories in 2022
mostpop_country = df.groupby('Country')['2022 Population'].sum().sort_values(ascending=False).head(5)

#Generate a bar plot of the top 5 most populated countries of 2022
fig = px.bar(x=mostpop_country.index,
             y=mostpop_country.values,
             color_discrete_sequence = ['MidnightBlue'],
             text=mostpop_country.values,
             title='Top 5 Most Populated Countries According to 2022 Population'
            )
#Update axis titles for clarity
fig.update_layout(xaxis_title='Country', yaxis_title='Population')
#Update hover information for addition clarity
fig.update_traces(hovertemplate='<br> Country: %{x} </br> 2022 Population: %{y}')

fig.show()

Notice:

• China and India are nearly tied for the largest country populations both hosting populations of roughly 1.4 billion
• China and India hold nearly 50% of the total world population within their borders alone
• The United States is the third most populated country in the world at around 340 million people
• Out of all the countries and territories, Asia has four out of the five most populated countries

#Calculate the top 5 least populated countries/territories of 2022
leastpop_country = df.groupby('Country')['2022 Population'].sum().sort_values(ascending=True).head(5)
leastpop_country = leastpop_country.sort_values(ascending=False)

#Generate a bar plot of the top 5 least populated countries/territories of 2022
fig = px.bar(x=leastpop_country.index,
             y=leastpop_country.values,
             color_discrete_sequence = ['IndianRed'],
             text=leastpop_country.values,
             title= 'Top 5 Least Populated Countires According to 2022 Population'
             )
#Update axis titles for clarity
fig.update_layout(xaxis_title='Country', yaxis_title='Population')
#Update hover information for additional clarity
fig.update_traces(hovertemplate='<br> Country: %{x} </br> 2022 Population: %{y}')
fig.show()

Notice:

• The Vatican City is the least populated territory in the world only hosting about 500 residents
• The five least populated countries in the world all have less than 4,500 people residing within each of them
• Four out of the five least populated countries and territories reside on islands
• Four out of the five least populated regions are territories rather than countries

We can try to determine if there are any changes in these rankings by looking at the most and least populated countries and territories of the past 50 years.

#Generate list of decades to cycle through for plotting
populations = ['2020 Population','2010 Population','2000 Population','1990 Population','1980 Population','1970 Population']
#Set list to chronological order
populations.reverse()

#Using a for loop, plot the top 5 least and most populated countries/territories for each decade over the past 50 years
for pop in populations:
    #Calculate the least and most populated countries/territories of each decade
    mostpop_country = df.groupby('Country')[pop].sum().sort_values(ascending=False).head(5)
    leastpop_country = df.groupby('Country')[pop].sum().sort_values(ascending=True).head(5)
    leastpop_country = leastpop_country.sort_values(ascending=False)

    #Generate subplot matrix for each decade
    fig = make_subplots(rows=1,cols=2,specs=[[{'type':'xy'},{'type':'xy'}]],
                   subplot_titles=['Top 5 Most Populated Countries','Top 5 Least Populated Countries'],
                   y_title='Population', x_title='Countries')
    #Generate bar chart for top 5 most populated countries of the decade
    fig.add_trace(
    go.Bar(x=mostpop_country.index,
           y=mostpop_country.values,
           texttemplate='%{y}',
           name='',
           showlegend=False,
           marker=dict(color='MidnightBlue')
    ),
    row=1,
    col=1
    )
    #Generate bar chart for top 5 least populate countries of the decade
    fig.add_trace(
    go.Bar(x=leastpop_country.index,
           y=leastpop_country.values,
           texttemplate='%{y}',
           name='',
           showlegend=False,
           marker=dict(color='IndianRed')
    ),
    row=1,
    col=2
    )
    #Include a main title indicating which decade the subplots are refering to
    fig.update_layout(title_text=pop)
    fig.show()

Notice:

• The top four most populated countries have remained the same over the past 50 years: China, India, United States, and Indonesia
• The Vatican City has remained the least populated territory in the world for the past 50 years and has actually shrunk in population
• Saint Barthelemy's population doubles from 1970 to 1990 until it eventually made its way out of the 5 least populated countires and territories

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